Thin, flexible polyurethane foam film layers have long been known in the art for use in laminates comprising the foam films and surfacing sheets or films of synthetic resins such as vinyls, urethanes, polyesters and the like. Often, the foam film is backed with a textile or fabric layer which adds strength to the laminate and the surfacing film is formed of a solid synthetic resin of extremely thin film thickness which merely gives ornamentation and esthetically pleasing surfacing to the laminate. Such combined materials are often used as clothing fabrics, leather substitutes and in other applications where leather and textile piece goods had previously been used.
The function of the urethane foam film in such laminates is to provide bulk, improve the hand of the material and stop the weave in underlying textile fabrics from showing through upon application of pressure to the skin layer as might be caused by bendng of the laminate.
There have been certain difficulties in obtaining thin flexible polyurethane foam films of uniform thickness for use in such fabric laminates. Ordinarily, the foam films are formed by conventional urethane foaming techniques which include the use of a water catalyst to generate carbon dioxide thus forming the foam. This often results in nonuniform density and film layer thickness in the final film and/or the need for mechanically confining the film during foam formation. Freon has been used to form foams in the past. However, blowing with Freon is hard to control, often requires confined molding and is not suitable for efficient production of thin urethane foam films. Continuous production methods for forming such thin polyurethane flexible foam films and producing laminates thereof with skin and textile layers often create difficulties using conventional techniques.